package com.ruis.kotboot.common.plug;

import org.bouncycastle.jce.provider.BouncyCastleProvider;

import javax.crypto.Cipher;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;
import java.security.AlgorithmParameters;
import java.security.Key;
import java.security.Security;

/**
 * Created by mgr on 2017/5/18.
 */
public class AESUtils {
    private static boolean initialized = false;
    /**
     * AES解密
     * @param content 密文
     * @return
     */
    public static byte[] decrypt(byte[] content, byte[] keyByte, byte[] ivByte) throws Exception {
        initialize();
        Cipher cipher = Cipher.getInstance("AES/CBC/PKCS7Padding");
        Key sKeySpec = new SecretKeySpec(keyByte, "AES");

        cipher.init(Cipher.DECRYPT_MODE, sKeySpec, generateIV(ivByte));// 初始化
        byte[] result = cipher.doFinal(content);
        return result;
    }

    private static void initialize(){
        if (initialized) return;
        Security.addProvider(new BouncyCastleProvider());
        initialized = true;
    }
    //生成iv
    private static AlgorithmParameters generateIV(byte[] iv) throws Exception{
        AlgorithmParameters params = AlgorithmParameters.getInstance("AES");
        params.init(new IvParameterSpec(iv));
        return params;
    }
}
